Topic
Active EMI reduction
About: Active EMI reduction is a research topic. Over the lifetime, 4 publications have been published within this topic receiving 21 citations.
Papers
TL;DR: In this article, a chaotic triangular ramp generator is constructed from a simple on-chip chaotic circuit linked with a symmetrically triangular ramp circuit to reduce the EMI in DC-DC buck converters.
Abstract: DC-DC buck converters are widely used in portable applications because of their high power efficiency. However, their inherent fast switching releases electromagnetic emissions, making them prominent sources of electromagnetic interference (EMI). This paper proposes a voltage-controlled buck converter that reduces EMI by using a chaotic pulse-width modulation (PWM) technique based on a chaotic triangular ramp generator. The chaotic triangular ramp generator is constructed from a simple on-chip chaotic circuit linked with a symmetrically triangular ramp circuit. The proposed converter can thus operate in the chaotic mode reducing the EMI without requiring any EMI filters. Additionally, using the triangular ramp signal can relax the requirement for a large LC output filter in chaotic mode. The effectiveness of the proposed scheme was experimentally verified with a chaotic triangular ramp generator embedded in a voltage-mode controller buck converter using a 0.18 µm Complementary Metal Oxide Semiconductor (CMOS) process. The measurement results from a prototype showed that the EMI improvement from the proposed scheme is approximately 14.53 dB at the fundamental switching frequency with respect to the standard fixed-frequency PWM reference case.
16 citations
1 Sep 2019
TL;DR: Simulation and experimental results are provided to verify the effectiveness of proposed randomized switching frequency PWM technique in reducing and smoothing the conducted emissions’ undesirable peaks within concerned frequency range.
Abstract: Random modulations are considered to be one of the viable solutions for mitigating conducted electromagnetic interference (EMI) in power converters. However, there are rarely literatures investigating this technique in grid-tied active frond end (AFE) drives. In this paper, a modulation scheme for grid-tied AFE converter based on uniformly randomized switching frequency PWM is proposed. The proposed technique features the advantage that it requires no additional hardware modification of the grid-tied AFE motor drive system but some convenient algorithm adjustment in digital implementation. Simulation and experimental results are provided to verify the effectiveness of proposed randomized switching frequency PWM technique in reducing and smoothing the conducted emissions’ undesirable peaks within concerned frequency range.
14 citations
TL;DR: This approach describes a hybrid method preserving the good dynamic performances of an analog switching regulator controller and adding the flexibility of controlling the output voltage by adjusting the duty cycle value of a DPWM signal and thus controlling the average voltage value of the signal applied in the feedback circuit of a DC-DC converter.
4 citations
11 Oct 2020
TL;DR: In this paper, the authors proved that the rectangular waveform's harmonics energy is only related with average duty cycle and voltage level, and rearranging the harmonics magnitude with the optimized switching angles, the EMI filter size can be significantly reduced compared with the fixed switching frequency control.
Abstract: The fast switching speed of the GaN devices in DC-DC converters significantly increase the EMI noise in high frequencies. Passive and active EMI reduction techniques are usually applied in power converters to reduce the EMI noise. With no extra components, spectrum spread techniques becomes more and more popular in EMI noise reduction. Conventional spectrum spread techniques such as switching frequency modulation, averagely relocates the EMI energy near its switching frequency which is not always helping to reduce the EMI filter’s size. By controlling the switching angles, the magnitude of the harmonics can be determined, and the EMI spectrum can be steered regarding to the EMI filter’s attenuation performance. In this paper, it is proved that the rectangular waveform’s harmonics energy is only related with average duty cycle and voltage level. By rearranging the harmonics magnitude with the optimized switching angles, the EMI filter size can be significantly reduced compared with the fixed switching frequency control. And compared with conventional spectrum spread techniques, the proposed technique can further reduce the EMI filter size and fully use the EMI filter’s attenuation abilities.
2 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2020 | 1 |
| 2019 | 1 |
| 2018 | 2 |